Processor	80486SX/80486DX/80486DX2/80486DX4/Pentium Overdrive
Processor Speed	25/33/40/50(internal)/66(internal)/100(internal)MHz
Chip Set	INTEL
Max. Onboard DRAM	128MB
Cache	64/256KB
BIOS	AMI
Dimensions	330mm x 218mm
I/O Options	Floppy drive interface, IDE interface,mouse connector, parallel port, P/S2 mouse connector, serial ports (2), VGA connector
NPU Options	None

CONNECTIONS
Purpose	Location	Purpose	Location
Bus mouse connector	CN1	IDE LED	J11
P/S2 mouse connector	CN4	Green power supply connector	J16
Floppy drive interface	CN6	Turbo switch	J29
IDE connector	CN7	Turbo LED	J30
Serial port 1	CN8	Reset switch	J31
Serial port 2	CN9	Speaker	J32
Parallel port	CN10	Power LED & keylock	J33
SCSI connector	CN11	PCI slots	PCI 1, 2, & 3
SCSI busy LED	J7	3.3V daughter board (80486DX4)	PS3V

USER CONFIGURABLE SETTINGS
Function		Jumper	Position
»	CPU generate parity	J4	pins 1 & 2 closed
	DPU generate parity	J4	pins 2 & 3 closed
»	Do not force parity error	J5	pins 1 & 2 closed
	Force parity error	J5	pins 2 & 3 closed
»	SCSI enable	J6	closed
	SCSI disable	J6	open
»	SCSI power source from peripheral device	J8	open
	SCSI power source from system	J8	closed
	IDE connector pin 27 linked to IOCHRDY signal	J9	closed
	IDE connector pin 27 open	J9	open
	IDE connector pin 28 linked to BALE signal	J10	closed
	IDE connector pin 28 open	J10	open
»	Normal operation	J17	Open
	Clear password	J17	closed
»	Saturn B-step chip	J23	pins 1 & 2 closed
	Saturn II/II-50	J23	pins 2 & 3 closed
»	Cache set at 256K	J24	pins 2 & 3 closed
	Cache set at 64K	J24	pins 1 & 2 closed
	Level 2 write-back cache	J25	pins 1 & 2 closed
	Level 2 write-through cache	J25	pins 2 & 3 closed
»	80486DX4 2.5X mode	J26	pins 2 & 3 closed
	80486DX4 2X mode	J26	pins 1 & 2 closed
	80486DX4 3X mode	J26	open
»	Pentium Overdrive internal write-back cache	J27	pins 1 & 2 closed
	Pentium Overdrive internal write-through cache	J27	pins 2 & 3 closed
»	No cache wait state	JF3	pins 2 & 3 closed
	One cache wait state	JF3	pins 1 & 2 closed
	Saturn II/II-50 chipset with SL-enhan/DX4/Pentium overdrive	JF9	pins 2 & 3 closed
	Saturn II/II-50 chipset with other CPUs	JF9	pins 1 & 2 closed
	Saturn II/II-50 chipset for Saturn B-step chipset use	JF9	open
»	PCI SCSI IRQ at IRQ9	JN1	pins 1 & 2 closed
	PCI SCSI IRQ at IRQ11	JN1	pins 2 & 3 closed

DRAM CONFIGURATION
Size	Bank 0	Bank 1	Bank 2	Bank 3
2MB	(1) 256K x 36	(1) 256K x 36	NONE	NONE
4MB	(1) 256K x 36	(1) 256K x 36	(1) 256K x 36	(1) 256K x 36
8MB	(1) 1M x 36	(1) 1M x 36	NONE	NONE
10MB	(1) 1M x 36	(1) 1M x 36	(1) 256K x 36	(1) 256K x 36
16MB	(1) 1M x 36	(1) 1M x 36	(1) 1M x 36	(1) 1M x 36
32MB	(1) 4M x 36	(1) 4M x 36	NONE	NONE
34MB	(1) 4M x 36	(1) 4M x 36	(1) 1M x 36	(1) 256K x 36
40MB	(1) 4M x 36	(1) 4M x 36	(1) 1M x 36	(1) 1M x 36
64MB	(1) 4M x 36	(1) 4M x 36	(1) 4M x 36	(1) 4M x 36
64MB	(1) 16M x 36	(1) 16M x 36	NONE	NONE

DRAM CONFIGURATION (CONTINUED)
Size	Bank 0	Bank 1	Bank 2	Bank 3
66MB	(1) 16M x 36	(1) 16M x 36	(1) 256K x 36	(1) 256K x 36
72MB	(1) 16M x 36	(1) 16M x 36	(1) 1M x 36	(1) 1M x 36
96MB	(1) 16M x 36	(1) 16M x 36	(1) 16M x 36	(1) 16M x 36
128MB	(1) 16M x 36	(1) 16M x 36	(1) 16M x 36	(1) 16M x 36
Note:A {(1) 32M x 36} is a double RAS SIMM.

CACHE CONFIGURATION
Size	Data RAM	TAG RAM	U32 (dirty bit)
64KB	(8) 8K x 8	(1) 1K x 8	64K x 1
256KB	(8) 32K x 8	(1) 32K x 8	64K x 1

CACHE JUMPER CONFIGURATION
Size	J14	J15	J18	J19
64KB	Open	Open	Open	Open
256KB	Closed	Closed	Closed	Closed

CACHE INTERLEAVE CONFIGURATION
Type	J20	J21	J22
Interleave	pins 2 & 3 closed	pins 1 & 2 closed	pins 1 & 2 closed
Standard	pins 1 & 2 closed	pins 2 & 3 closed	pins 2 & 3 closed
Note:Interleave setting is for the Saturn II-50 chipset only.

CPU TYPE CONFIGURATION
Type	JC1	JC2, JC3
80486SX	Open	pins 2 & 3
80486DX	Open	pins 1 & 2
80486DX2	Open	pins 1 & 2
80486DX4	Open	pins 1 & 2
Pentium Overdrive	Closed	pins 1 & 2

CPU TYPE CONFIGURATION (CONTINUED)
Type	JC4, J12	JC5	JC6
80486SX 1	Closed	Open	pins 1 & 2
80486SX 2	Closed	Open	pins 1 & 2
80486DX 1	Closed	Open	pins 1 & 2
80486DX 2	Closed	Open	pins 1 & 2
80486DX2 1	Closed	Open	pins 1 & 2
80486DX2 2	Closed	Open	pins 1 & 2
80486DX4 1	Closed	Open	pins 1 & 2
80486DX4 2	Closed	Closed	pins 2 & 3

CPU TYPE CONFIGURATION (CONTINUED)
Type	JC4, J12	JC5	JC6
SL enhanced 1	Closed	open	pins 1 & 2
SL enhanced 2	Closed	closed	pins 2 & 3
Pentium Overdrive 1	Open	open	pins 1 & 2
Pentium Overdrive 2	Open	closed	pins 2 & 3
Note: 1 denotes Saturn B-step chipset used with CPU.
2 denotes Saturn II/II-50 chipset used with CPU.

CPU CLOCK (VT8225N) CONFIGURATION
Speed	JK1	JK2
CLK2 50 Mhz	pins 1 & 2 closed	pins 2 & 3 closed
CLK2 66.6 Mhz	pins 2 & 3 closed	pins 1 & 2 open

CPU SPEED CONFIGURATION
Speed	JF6	JF7
Reserved	pins 2 & 3	pins 1 & 2
25MHz	pins 1 & 2	pins 1 & 2
33Mhz	pins 1 & 2	pins 2 & 3
50iMHz	pins 1 & 2	pins 1 & 2
50iMHz 1	pins 2 & 3	pins 2 & 3
66iMHz	pins 1 & 2	pins 2 & 3
Note: 1 denotes Saturn II-50 chipset only.

PCI1 IRQ SELECTION
Jumper	IRQ	Setting
JI1	IRQ5	pins 1 & 2 closed
JI2	IRQ9	pins 1 & 2 closed
JI3	IRQ10	pins 1 & 2 closed
JI4	IRQ11	pins 1 & 2 closed
JI5	IRQ12	pins 1 & 2 closed
JI6	IRQ14	pins 1 & 2 closed
JI7	IRQ15	pins 1 & 2 closed

PCI2 & PCI3 IRQ SELECTION
Jumper	IRQ	Setting
JI1	IRQ5	pins 2 & 3 closed
JI2	IRQ9	pins 2 & 3 closed
JI3	IRQ10	pins 2 & 3 closed
JI4	IRQ11	pins 2 & 3 closed
JI5	IRQ12	pins 2 & 3 closed
JI6	IRQ14	pins 2 & 3 closed
JI7	IRQ15	pins 2 & 3 closed

TAG ADDRESS CONFIGURATION
Address	JF1	JF2
8-bit	pins 1 & 2 closed	pins 1 & 2 closed
7-bit	pins 1 & 2 closed	pins 2 & 3 closed
9-bit	pins 2 & 3 closed	pins 1 & 2 closed
Reserved	pins 2 & 3 closed	pins 2 & 3 closed

MISCELLANEOUS TECHNICAL NOTE

Note:1. When using the PCI1 slot on the mainboard, jumper choice should only be limited to pins 1 & 2 of jumpers JI1 to JI7

2. When using PCI2 or PCI3 slots on the mainboard, jumper choice should only be limited to pins

2 & 3 of jumpers JI1 to JI7.

3. When using the Saturn B-step chipset, PCI1 slot serves as the master slot while PCI2 and PCI

3 slots serve as slave slots.

4. When using the Saturn II/II-50 chipset, PCI1, PCI2, PCI3 slots can serve both as master or

slave slot.